The Gaddafi regime has issued a defiant warning that the "time for action" had arrived as a sustained military assault forced the defeat of Libyan rebels in the strategically important town of Zawiya and their retreat from Ras Lanuf.

Amid squabbling among EU and Nato leaders on the eve of an emergency European summit on Libya in Brussels, Muammar Gaddafi's son said that a new offensive would be launched within days.

"It's time for liberation. It's time for action," Saif al-Islam told Reuters after the defeat of opposition forces in the town of Zawiya, 30 miles from Tripoli, and the rout of rebels in the town of Ras Lanuf. He added: "We are moving now."

The tough rhetoric from the Gaddafi regime – and its apparent success on the ground against the rebels – set the scene for a difficult emergency EU summit where leaders are expected to clash on the military and diplomatic resp